A report by the Ministry of Justice has given a broadly clean bill of health to the process of trial by jury

Ministry of Justice research has debunked some myths about juries, including the idea that they discriminate against black defendants or won't ­convict rapists, or that there are some crown courts where the police are unlikely to get convictions.

The study – Are Juries Fair? – was ­carried out by Professor Cheryl Thomas of University College, London, and is based for the first time on interviews with more than 1,000 jurors after their cases. It also undertakes a separate study of 68,000 jury verdicts to examine the sensitive issue of how juries make their decisions.

The report delivers a strong endorsement of the role of the jury in the criminal justice system, concluding that juries in England and Wales were found to be fair, effective and efficient.

It does recommend, however, that more could be done to help them perform their task in the wake of concerns raised by Lord Judge, the lord chief justice, that jurors are having increasing difficulties in listening to evidence and understanding oral instructions.

The study also looked for the first time at the impact of pre-trial media reporting on cases, but the findings appear to be inconclusive as to the extent coverage actually influences what goes on in the jury room. The study found that 35% of jurors in high-profile cases remembered pre-trial coverage, but only 20% of that group, or 7% of the total sample, said they found it difficult to put the reports out of their mind during the case.

The study did, however, find that a quarter of jurors sitting in high-profile cases admitted to looking for information on the internet about their case while it was going on, despite being told by the judge not to do so.

The research included case simulations with 41 all-white juries at Winchester and Nottingham crown courts which showed no tendency for them to convict a black or Asian defendant more than a white one.

But it did find that all-white juries in Nottingham, a racially diverse area, appeared to be more sensitive in cases involving racial conflict and were more likely to convict a white defendant accused of assaulting a black victim.

In rape cases the study found that, contrary to popular belief and previous official reports, juries convict more often than they acquit, with a 55% conviction rate in crown court rape trials. It said that a previous Home Office study which found that they were more likely to acquit than convict was based on only 181 verdicts in a small number of courts compared with the 4,310 verdicts in this study.

It concludes that juries are not primarily responsible for the low conviction rate following rape allegations and that juries are more reluctant to convict in cases of attempted murder and grievous bodily harm than in rape cases.

The research also dismisses claims that men sitting on juries are less likely than women to listen to the arguments and change their minds.

Overall, it gives a strong endorsement of the jury system, saying that they appear to try cases on the evidence and the law, with those cases based on the strongest direct evidence having the highest conviction rates.

Professor Thomas said: "This research shows that juries in England and Wales were to be found to be fair, effective and efficient – and should lay to rest any lingering concerns that racially-balanced juries are needed to ensure fairness in trials with black and minority ethnic defendants or racial evidence."The study demonstrates that in-depth research into what goes on in the jury room is possible despite the Contempt of Court Act confidentiality clause on their proceedings.

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